Wavelength-shift composite light-storing powder and method of manufacturing and applying the same

ABSTRACT

A wavelength-shift composite light-storing powder and method of manufacturing and applying the same. Wherein, inorganic metal oxide and light-storing material containing rare earth elements are made to collide at high speed in an environment of extremely low temperature. The collision process makes said inorganic metal oxide to produce fusion reaction on surface of said light-storing material, that causes changes of lattice structure, to generate photon shift phenomenon and produce said wavelength-shift composite light-storing powder. Said composite light-storing powder is apt to engage cross-linked structure of thermoplastic polymer in a high temperature blending process, to achieve even distribution. Finally, through a filament process to produce successfully light-storing fibers capable of emitting lights of various wavelengths, to raise its heat resistance and wash durability.

REFERENCE TO RELATED APPLICATION

The present application is a divisional application of U.S. applicationSer. No. 13/946,139, filed Jul. 19, 2013, which claims priority toTaiwanese Application Serial Number 102115123, filed Apr. 26, 2013. Theentire disclosures of all the above applications are hereby incorporatedby reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a light-storing material, and inparticular to a wavelength-shift composite light-storing powder andmethod of manufacturing and applying the same, that is made throughusing an inorganic metal oxide.

2. The Prior Arts

Since the discovery of the long afterglow phenomenon in the early20^(th) century, the development of the light-storing material hasprogressed rapidly. Various light-storing materials are utilizedextensively in the manufacturing of the light-storing objects. Thelight-storing material is able to emit specific lights after absorbingultra-violet light or other radiations, and that is referred to as thefluorescence light or afterglow. The light-storing material can be madeinto light-storing fiber, that is able to absorb sun light, ultravioletlight in daytime, to store it as light energy, and in darkness or atnight, it can give out lights of various colors. The costume made oflight-storing fiber is colorful and glamorous, without the need to usedye. As such, it can avoid environment pollution, being non-toxic andun-harmful, having no radioactivity, thus fulfilling the requirement ofenvironment protection.

With regard to the related patent case, Taiwan Patent No 564268discloses “A night time high luminance fiber and method of manufacturingthe same”. Wherein, it provides a night time high luminance fiber,having the characteristics of long time high luminance multi-coloremission, without causing harm to the human body, as such it can be usedin embroidery and garments. The fiber is a kind of a shell and core typecomposite fiber, formed by polyester resin or polyolefin resin of nightluminance pigment as its core, and polyester resin not containing thenight luminance pigment as its shell. In contrast to the pure fiber, itcontains night luminance pigment of 7 to 25% by weight, and one minuteafter termination of agitation, it can still retain residue luminance ofover 500 mcd/m². For a single fiber, its diameter is below 40 μm.

In addition, Taiwan Patent No. 200927883 discloses a “Wash durabilitylight-storing masterbatch and fiber, and method of manufacturing thesame”. Wherein, it emphasizes the use of hydrophobic material, to mix itwith light-emitting material such as aluminate salts having rare earthelements, to produce light-storing masterbatches. Then, it goes througha melting and spinning process, to form a shell and core typelight-storing fiber. The use of hydrophobic material is to devoid thelight-storing material in the light-storing fiber from the problem ofhydrolysis due to moisture.

However, usually, the conventional light-storing fiber must use highcontents of light-storing powder, about 30% by weight, thus it has thedrawback of high production cost, monotonous emitted light color, and itcan not be mass produced. Also, it has the problem of insufficient heatresistance for the spinning and yarning processes, and the fiberapplying process does not have wash durability, and can not withstandfilament processing and rectification.

Therefore, there exists a need in the Industries to develop a lightstoring material that is heat resistant and wash durable, and can bemass produced to emit lights of various colors, so as to achieve ideallight-storing fiber or fabric, to increase its application scope andcompetitiveness.

SUMMARY OF THE INVENTION

In view of the problem and drawbacks of the prior art, a major objectiveof the present invention is to provide a wavelength-shift compositelight-storing powder and a method of manufacturing and applying thesame, that is realized through high speed collisions in an environmentof extremely low temperature, so that the metal ions of inorganic metaloxide can be imbedded into the structure defects of the light-storingmaterial, to cause photon jump across energy gap, to produce thecomposite light-storing powder of cool color series light wavelength. Assuch, the single wavelength light emission of the light-storing materialof the prior art can be upgraded to the multi wavelength light emissionof the composite light-storing powder of the present invention, toincrease its application scope and competitiveness.

Another objective of the present invention is to provide awavelength-shift composite light-storing powder and method ofmanufacturing and applying the same, to enable the light-storingmaster-batch and the light-storing fiber to emit lights of variouscolors in contrast to the prior art, to raise the heat resistance andwash durability of the light-storing fiber, so as to reduce Deniernumber and amount utilized.

In order to achieve the objective mentioned above, the present inventionprovides a wavelength-shift composite light-storing powder, composed oflight-storing material containing rare earth elements, and inorganicmetal oxide. Wherein, the inorganic metal oxide is fused and formed onthe surface of light-storing material containing rare earth elements, ina high speed gas flow, and in an environment of extremely lowtemperature −100 to −196° C., to cause change of energy and producewavelength-shift phenomenon. The wavelength-shift compositelight-storing powder of the present invention is capable of emittinglights of various colors, to produce lights of different wavelengths atdifferent times.

The present invention also provides a wavelength-shift compositelight-storing powder manufacturing method, including the followingsteps. Firstly, provide a light-storing material containing rare earthelements and inorganic metal oxide. Next, introduce in a high speed gasflow, and in an environment of extremely low temperature −100 to −196°C., to make light-storing material having rare earth elements, andinorganic metal oxide to collide at high speed. Then, utilize theinstantaneous high temperature caused by the collision and the extremelylow temperature of the environment, to make the metal ions of theinorganic metal oxide to produce fusion reaction, to change the latticestructure of the light-storing powder containing rare earth elements, soas to obtain the wavelength-shift composite light-storing powder.

The present invention also provides a light-storing fiber manufacturingmethod, including the following steps. Firstly, mix the multi-wavelengthcomposite light-storing powder of 1 to 30% by weight into thermoplasticpolymer of 50 to 95 weight %, ring structure agent having a dipropyleneand a tripropylene functional group of 0.05 to 5% by weight, crosslinking agent of 0.01 to 5% by weight, and dispersing agent of 0.01 to5% by weight, to obtain a mixed powder. Subsequently, put the mixedpowder in a high temperature to melt and blend, so that thethermoplastic polymer is in a melted condition. Then, cross link themelted thermoplastic polymer, to make the composite light-storing powderto distribute evenly in the cross-linked thermoplastic polymer.Subsequently, bake to dry the cross linked thermoplastic polymer havingthe composite light-storing powder distributed therein, to obtain thelight-storing masterbatches. Afterwards, perform spinning and filamentprocess for the light-storing masterbatches, and to make the filamentscurl into light-storing fibers. The production process described abovecan raise the heat resistance of the light-storing fiber, to producesuccessfully the light-storing filament fiber. As such, even after itbeing washed 50 times with water, it can still retain sufficientluminance. The light-storing fiber of the present invention can be usedextensively in various Industries, such as the commodity industry,textile industry, indoor decoration products, and safety products.

Further scope of the applicability of the present invention will becomeapparent from the detailed descriptions given hereinafter. However, itshould be understood that the detailed descriptions and specificexamples, while indicating preferred embodiments of the presentinvention, are given by way of illustration only, since various changesand modifications within the spirit and scope of the present inventionwill become apparent to those skilled in the art from this detaileddescriptions.

BRIEF DESCRIPTION OF THE DRAWINGS

The related drawings in connection with the detailed descriptions of thepresent invention to be made later are described briefly as follows, inwhich:

FIG. 1 is a flowchart of the steps of a wavelength-shift compositelight-storing powder manufacturing method according to the presentinvention;

FIG. 2 is a flowchart of the steps of light-storing masterbatchesmanufacturing method according to the present invention;

FIG. 3. is a flowchart of the steps of light-storing fiber manufacturingmethod according to the present invention; and

FIG. 4 is a diagram showing light spectrum energy distribution curvesfor a comparison example and embodiments 1 and 2 according to thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The purpose, construction, features, functions and advantages of thepresent invention can be appreciated and understood more thoroughlythrough the following detailed description with reference to theattached drawings.

The present invention provides a wavelength-shift compositelight-storing powder, that is upgraded from the original singlewavelength light emission to the multi-wavelength light emission.Through the blending and spinning technology of the light-storingmasterbatch, the light-storing fiber capable of emitting lights ofvarious wavelengths can be produced. In the following, refer to FIGS. 1to 3 as to details about how to produce wavelength-shift compositelight-storing powder, and then the ways of processing it intolight-storing masterbatch and light-storing fiber.

Refer to FIG. 1 for a flowchart of the steps of a wavelength-shiftcomposite light-storing powder manufacturing method according to thepresent invention, including the following steps.

Firstly, as shown in step S10, provide light-storing material containingrare earth elements of 0.1 to 5 weight %, and inorganic metal oxide of0.01 to 5 weight %. Wherein, SrAl₂O₄:Eu,Td can be chosen to use for thelight-storing material containing rare earth elements; while theinorganic metal oxide can be selected from one of a group consisting of:zinc oxide, aluminum oxide, calcium oxide, magnesium oxide, zirconiumoxide, strontium oxide.

Next, as shown in step S20, introduce in high speed gas flow, such as100% nitrogen, to establish an environment of relatively low temperatureof −100° C. to −196° C., so that light-storing material containing rareearth elements is made to collide with the inorganic metal oxide at highspeed. In this collision process, collision heat of instantaneous hightemperature on the surface of the light-storing material, can make themetal ions of the inorganic metal oxide to produce fusion reaction dueto high temperature, hereby leading to change of lattice structure ofthe light-storing material due to its defect being filled, thus theemitted photon will produce the photon shift effect, namely, the photonsgetting more energy, so that the wavelength is shortened. Moreover,through the instant cooling provided by the environment of extremely lowtemperature, the fusion reaction only occurs at the surface of thelight-storing material, and will not cause the luminance to deterioratesignificantly. Due to the jumping of electrons across energy gap andimbedded filling of the structure defect, the photon scattering producedby the light agitated free electrons can be reduced for reduction ofdefects. Also, that will delay the time for the free electrons jumpingback to the ground state, to increase light emitting duration.

In the present invention, the wavelength-shift composite light-storingpowder is capable of producing lights of multi-color through variationsof lattice structure, so that the main peak wavelength of light emittedfrom the light-storing material SrAl₂O₄:Eu,Td can be shifted from theoriginal 565 nm of green light wavelength to the 505 nm and 485 nm ofblue-green series light wavelengths.

Next, refer to FIG. 2 for a flowchart of the steps of light-storingmasterbatch manufacturing method according to the present invention. Asshown in FIG. 2, the method includes the following steps:

As shown in step S30, mix the wavelength-shift composite light-storingpowder of 1 to 30% by weight into the dried thermoplastic polymer. Theamount of thermoplastic polymer utilized is 50 to 95% by weight, whichcan be chosen from polyester powder, nylon powder, polyester particles,or nylon particles. Wherein the Intrinsic Viscosity (IV) of thepolyester powder is 0.2 to 2.0; while the relative viscosity (RV) of thenylon powder is 2.0 to 5.0. Then, add in ring structure agent having adipropylene and a tripropylene functional group of 0.05 to 5 weight %,cross linkage agent of 0.01 to 5% by weight, and dispersing agent of0.01 to 5 weight %, to mix them evenly into a mixed powder.

In the descriptions above, the ring structure agent having dipropyleneand tripropylene functional groups can be chosen from one in a groupconsisting of: diallylphthalate,diallyl succinate,diallyltartramide,triallyl amine,triallyl trimesate,2,2-thiobis(p-tert-octylphenolate)nickel,triallyl cyanurate,triallylisocynaurate,(4-[[4-(aminocarbonyl)phenyl]azo]-N-(2-ethoxyphenyl)-3-hydroxynaphthalene-2-carboxamide)and triacryloylhexahydro-1,3,5-triazine. The dispersing agent can bechosen from the long carbon chain Alkane dispersing agent, that forexample can include wax.

Next, as shown in step S40, in a blending temperature of 180° C. to 260°C., melt and blend the mixed powder, to make the thermoplastic polymerin a melted state. Through the cross linking reaction between the crosslinking agent and the thermoplastic polymer, to make the compositelight-storing powder to distribute evenly in the cross-linkedthermoplastic polymer.

Then, as shown in step S50, bake the mixture to dry in a temperature of85° C., to produce the light-storing masterbatch.

Refer to FIG. 3 for a flowchart of the steps of light-storing fibermanufacturing method according to the present invention, comprising thefollowing step.

Firstly, as shown in step S60, in a spinning temperature of 230 to 290°C., and at a spinning and curling speed of 1000 to 3000 m/min, performmelting and spinning of the light-storing masterbatches into filaments.

Finally, as shown in step S70, perform curling of the filaments intolight-storing fibers. The diameter of the light-storing fiber can be 20to 30 μm, and it can be a single-component fiber, or a double-componentfiber of a shell and core structure, such that the compositelight-storing powder can be formed into the shell or the core in adouble-component fiber of shell and core structure.

In the following, a few embodiments (the first and second embodiment)are described to explain the approaches of manufacturingwavelength-shift composite light-storing powder, and the ways ofprocessing it into a light-storing masterbatch and light-storing fiber.Also, a comparative example is used to explain the objective, principleand effect of the present invention.

(1) Wavelength-Shift Composite Light-Storing Powder.

For the light-storing material powder (SrAl₂O₄:Eu,Td) containing rareearth elements and inorganic metal oxide (zinc oxide and aluminumoxide), introduce continuously the liquid nitrogen, and in an extremelylow temperature (−100 to −196° C.), and under the introduction of highspeed gas flow, to make the two powders to collide, to achieve aproduction rate of 100-500 kg/h. Due to the extremely low environmenttemperature, and the instant pulverization produced by the powdercollision, the powder diameter will be reduced from 50 microns to below1 to 5 microns. Also, Due to the instantaneous heat produced bycollisions between the two kinds of powders, plus the extremely lowtemperature of the environment outside, thus causing the light-storingmaterial and the inorganic metal oxide to form temporary or permanentfusion, to produce the wavelength-shift composite light-storing powder.The change of lattice structure of the wavelength-shift compositelight-storing powder leads to the change of wavelength of light emitted.In the present invention, the wavelength-shift composite light-storingpowder thus produced changes the wavelength of lights emitted from thegreen light for the original light-storing material of the prior art, tothe cool color series wavelength, such as sky blue, ocean blue of theblue-green color series wavelengths.

It has to be specifically mentioned that, the zinc oxide and aluminumoxide themselves do not have light emitting capability. In the case ofsimple and direct mixing, the emitted photons will be affected by thepowder to produce serious scattering to restrict light emitting, thus itwill not produce photon shift. In the present invention, for the highspeed collision and fusion of the powders, in case fusion does notoccur, then it could not produce color change of the emitted light, alsothe luminance of light will be reduced markedly. Therefore, it is ableto determine if fusion is successful directly through the light emittingeffect.

(2) Light-Storing Masterbatch

Continue the manufacturing process mentioned above, prepare compositelight-storing powder of 10 to 25% by weight, together with polyester(PBT) powder, then add ring structure agent of 0.05 to 5 weight % havingdipropylene and tripropylene functional groups, long carbon chain Alkanedispersing agent of 0.5 to 1.5% by weight, to blend them together, thenadd light sensitive cross linking agent of 0 to 3.0% by weight having 3functional groups, as shown in Table 1. Subsequently, use a double-axisblending machine to blend it into Light-Storing Masterbatch at ablending temperature of 180 to 260° C. Since light sensitive crosslinkage agent having 3 functional groups is added, so that in thisenvironment of high blending temperature, the polyester Masterbatchoriginally having high crystallinity, will produce free radical crosslinking reaction, to form Interpenetrating Network Structure (IPN), toincrease the number of the non-fix type area, namely the non-crystallinearea. Then, bake the light-storing masterbatch thus obtained, and testluminance of the light-storing masterbatch. Table 2 shows the testresults, wherein, due to the increase of the cross linked structure, thenumber of the non-crystalline areas is increased. For the compositelight-storing powder in the polyester structure, since the crystallinearea could reduce light scattering, such that the luminance of thelight-storing masterbatch will increase due to the increase of the crosslinked structure. In addition, the viscosity of the light-storingmasterbatch is increased from 0.6 to 0.9, that is beneficial to thesubsequent spinning process, since in case the viscosity of thelight-storing masterbatch is to low, then filaments can not be formed.The remarkable luminance of the light-storing masterbatch can not onlyincrease the applicability of its product in the future, but it can alsoreduce the amount of the composite light-storing powder utilized inachieving cost reduction.

TABLE 1 cross linkage light- agent ring structure ring storing (wt %)inorganic Inorganic agent structure thermo material light metal metal(wt %) agent plastic (wt %) dispersing sensitive oxide oxide2,2-thiobis(p-tert- (wt %) polymer SrAl₂ agent cross (wt %) (wt %)octylphenolate) Trially (wt %) O₄:Eu, (wt %) linkage ZnO Al₂O₃ nickelamine PBT Td wax agent comparison 0 0 0.2 1.5 80.4 18 0.1 0 exampleEmbodiment 1 1 1 0.2 1.5 80.4 18 0.1 1.0 Embodiment 2 3 0 0.2 1.5 80.418 0.1 1.5

TABLE 2 Intrinsic viscosity (, I.V.) luminance after light afterglow oflight-storing emitting 2 minutes duration masterbatch (mcd/m²) (min)composite — 1288 3509 light-storing powder comparison 0.6 598 1823example Embodiment 0.82 1108 3523 1 Embodiment 0.89 1193 3581 2

3. Light-Storing Fiber

Continue the manufacturing process mentioned above, a composite spinningand curling machine is used to perform spinning of the light-storingmasterbatch, in a spinning temperature of 230 to 290° C. In the presentinvention, since the light-storing masterbatch is provided with thecross linking structure of Interpenetrating Network Structure (IPN), theviscosity of light-storing masterbatch can reach over 0.8, so that itsheat resistance is raised. Therefore, the spinning temperature of thespinning process can be raised, and the higher the temperature thehigher its fluidity, to increase the production speed and reduce thecost. Moreover, the filament curling speed can reach 1000 to 3000 m/mindue to increase of fluidity of the light-storing masterbatch; while thediameter of the fiber can be reduced from 6DPF to 120D/36F, that isabout 3DPF (the diameter of each fiber), as shown in the test results ofTable 3. In table 3, it shows that, the present invention indeed canproduce wavelength-shift light-storing fiber as required, and after testwash (AATCC135 test method) with water 50 times, luminance of fiber canbe maintained at 80 to 120 mcd/m².

Furthermore, refer to FIG. 4 for a diagram showing light spectrum energydistribution curves for a comparison example and embodiments 1 to 2according to the present invention. As shown in FIG. 4, curves (a), (b),(c) represent respectively the spectrum energy distribution curves forthe light-storing fiber of a comparison example and embodiments 1 to 2.The result indicates that, in the embodiments of the present invention,the peak of light wavelength emitted by the wavelength-shiftlight-storing powder is shifted from the green light wavelength 565 nm(curve (a)) for the light-storing material of the prior art, to theocean blue wavelength 505 nm (curve (b)), and the sky blue wavelength480 nm (curve (c)).

TABLE 3 light fiber luminance before luminance after wave- strengthwater wash water wash 50 times length (g/d, %) (mcd/m²) (mcd/m²) (nm)comparison 1.5 120 120 565 example embodiment 1.6 95 95 505 1 embodiment1.6 80 80 480 2

Summing up the above, the present invention provides a wavelength-shiftcomposite light-storing powder and method of manufacturing and applyingthe same. Wherein, inorganic metal oxide and light-storing materialcontaining rare earth elements are utilized, in an extremely lowtemperature and with a high temperature gas flow, to produce fusion ofmetal ions, to embed into structure defect of light-storing material, soas to change the route of the photons emitted, and the energy of thephotons. In this way, the energy levels of the ground state and theexcited state for the photons emitted are changed. In this approach,wavelength-shift composite light-storing powder can be made, of whichthe light-emitting characteristic is changed and is different from theoriginal light-storing material, and that is able to emit light ofdifferent wavelengths at different times.

Moreover, for the wavelength-shift composite light-storing powderproduced in the present invention, through the free radical cross linkreaction, plus 2- or 3-function group chemical reaction test agent, itcan produce a quantity of non-fixed areas, to increase the couplingreactions with the thermoplastic polymer, to reduce the cracks ofthermoplastic polymer incurred due to heat, so that the compositelight-storing powder can be distributed evenly in the thermoplasticpolymer. In addition, in the process of producing light-storingmasterbatch, the amount of the light-storing material containing rareearth elements is only 8 to 20% by weight, thus reducing the productioncost significantly.

For the reasons mentioned above, the light-storing fiber produced fromlight-storing masterbatch through the filament process is capable ofemitting light wavelength of various colors. Also, its heat resistance,fiber strength, and resilience are increased. Since its luminance israised, the amount of light-storing material utilized can be reduced. Inaddition, the Denier number and amount utilized for the light-storingfiber can be decreased, to maintain the visibility of 3 mcd/m² to thenaked eyes for more than 3 hours.

Through the application of the present invention, the amount utilizedfor the light-storing material can be reduced, yet the luminance of thelight-storing fiber produced can be raised, to achieve multi-color lightemission and long term wash durability. Therefore, it has a promisingfuture, and can be utilized in various Industries, such as the commodityindustry, textile industry, electronic industry, indoor decorationproducts, and safety products.

The above detailed description of the preferred embodiment is intendedto describe more clearly the characteristics and spirit of the presentinvention. However, the preferred embodiments disclosed above are notintended to be any restrictions to the scope of the present invention.Conversely, its purpose is to include the various changes and equivalentarrangements which are within the scope of the appended claims.

What is claimed is:
 1. A method of manufacturing a light-storing fiber,comprising following steps: mixing a plurality of wavelength-shiftcomposite light-storing powders of 1 to 30 wt %, a thermoplastic polymerof 50 to 95 wt %, a ring structure agent having a dipropylene or atripropylene functional group of 0.05 to 5 wt %, a cross linkage agentof 0.01 to 5 wt %, and a dispersing agent of 0.01 to 5 wt % to form amixed powder, wherein said plurality of wavelength-shift compositelight-storing powders comprises: a light-storing material containingrare earth elements; and an inorganic metal oxide forming and fusing ona surface of said light-storing material containing rare earth elementsunder a high speed gas flow and an environment with extremely lowtemperature −100 to −196° C.; blending said mixed powder to make saidthermoplastic polymer to be melted, and said melted thermoplasticpolymer is cross-linked through using said cross linkage agent, suchthat said wavelength-shift composite light-storing powders are dispersedin said cross-linked thermoplastic polymer; baking and drying saidcross-linked thermoplastic polymer having said wavelength-shiftcomposite light-storing powders dispersed therein to obtain alight-storing materbatch; melting said light-storing materbatch and spinit into a filament; and curling said filament into a light-storingfiber.
 2. The method of claim 1, wherein the temperature of saidblending is 180° C. to 260° C.
 3. The method of claim 1, wherein thetemperature of said drying is 85° C.
 4. The method of claim 1, whereinsaid thermoplastic polymer is polyester or nylon.
 5. The method of claim4, wherein the intrinsic viscosity (IV) of said polyester is 0.2 to 2.0;while the relative viscosity (RV) of said nylon is 2.0 to 5.0.
 6. Themethod of claim 1, wherein said ring structure agent having saiddipropylene or said tripropylene functional group is selected from agroup consisting of: diallylphthalate,diallyl succinate,diallyltartramide,triallyl amine,triallyl trimesate,2,2-thiobis(p-tert-octylphenolate)nickel,triallyl cyanurate,triallylisocynaurate,(4-[[4-(aminocarbonyl)phenyl]azo]-N-(2-ethoxyphenyl)-3-hydroxynaphthalene-2-carboxamide)and triacryloylhexahydro-1,3,5-tri azine.
 7. The method of claim 1,wherein said cross linkage agent is potassium perfulfate,azobisisbutyronitrile, or benzildimethylketal.
 8. The method of claim 1,wherein said dispersing agent is a long carbon chain alkane dispersingagent.
 9. The method of claim 1, wherein the diameter of saidlight-storing fiber is 20 μm to 30 μm.
 10. The method of claim 1,wherein said light-storing fiber is a single-component original fiber,or a double-component fiber of a shell and core structure, such thatsaid composite light-storing powder is formed into the shell or the coreof said double-component fiber.